Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility

Home | Task 2 | Subtask

Subtask: Geologic Framework and Holocene Coastal Evolution – Apalachicola Bay Region

Subtask Leader: David Twichell - USGS Woods Hole Science Center for Coastal and Marine Geology, Woods Hole, Massachusetts

Aim

The Apalachicola Bay estuary contains numerous oyster beds that support the largest oyster fishery in Florida. The distribution of the eastern oyster (Crassostrea virginica) is controlled by a variety of environmental factors including salinity, temperature, nutrient availability, suspended sediment concentrations, and substrate type. Information on the shallow stratigraphy and geologic framework of the bay, however, was insufficient to assess the influence the surficial and shallow subsurface geology may have on the distribution of oyster beds in this estuary. Results from this study provide necessary geological information about the floor of the bay and adjacent inner shelf for the continued effective management of this oyster fishery as well as the estuarine and coastal ecosystems of the region. This component of Subtask 2.1 focuses on understanding the role the shallow stratigraphy and geologic framework of the Apalachicola Bay part of the Florida panhandle have played in the evolution of this estuarine system and the role this history plays in its future.

Approach

The approach taken to address the aims of the project has been to conduct a comprehensive geophysical mapping of a large part of Apalachicola Bay and a part of the inner shelf offshore of the bay and collect cores to verify the geophysical observations. The geophysical datasets include continuous coverage sidescan sonar imagery, detailed bathymetry and high-resolution subbottom seismic-reflection profiles. The sidescan sonar imagery and bathymetry are being used to provide an accurate map of the locations and sizes of oyster beds in the bay. The high-resolution seismic-reflection profiles and cores are being used to define the evolution of the bay. The detailed oyster bed map is being used to monitor the health of this fishery and the improved understanding of the evolution of the bay over the last 6,000 years provides critical information for predictions for how this coastal region will respond to changes in climate, sea level, and coastal development.

Accomplishments

Sidescan-sonar imagery, bathymetry, high-resolution seismic profiles, and sediment cores show that oyster beds occupy the crests of a series of shoals that range from 1 to 7 km in length, trend roughly north-south perpendicular to the long axes of the bay and sound, and are asymmetrical with steeper sides facing to the west (Fig. 1). Surface sediment samples show that the oyster beds consist of shelly sand, while much of the remainder of the bay floor is covered by mud delivered by the Apalachicola River (Fig. 2). The present oyster reefs rest on sandy delta systems that advanced southward across the region between 6400 and 4400 yr BP when sea level was 4-6 m lower than present (Fig. 3A). Oysters started to colonize the region around 5100 BP and became extensive by 1200 and 2400 yr BP (Fig. 3B). Since 1200 yr BP, their aerial extent has decreased due to burial of the edges of the reefs by the prodelta mud that continues to be supplied by the Apalachicola River (Fig. 3C). Oyster reefs that are still active are narrower than the original beds, have grown vertically, and become asymmetrical in cross-section (Fig. 3D). Their internal bedding indicates they have migrated westward, suggesting a net westerly transport of sediment in the bay.

Conceptual illustration showing the development of the oyster reefs; view is from the south.
Figure 3: Conceptual illustration showing the development of the oyster reefs; view is from the south. (A) sea level at - 2.5 m, sediment supply was primarily sand in the form of southward advancing deltas. (B) sea level at -1 m, the delta surface was colonized by oysters, sediment supply was primarily prodelta mud. (C) sea level at its present elevation, oyster reefs were largely covered by the continued supply of prodelta mud with the exposed parts of the reefs growing vertically. (D) oyster reefs continue to grow vertically and migrate westward as their flanks are buried by prodelta mud.
[Enlargement]
Conceptual illustration showing the development of the oyster reefs; view is from the south.
Figure 1: Bathymetry of the Apalachicola Bay study area with five of the largest oyster reefs labeled in white. The 2, 3, and 4 m bathymetric contours are shown. ICW refers to the Intracoastal Waterway. The black squares show locations of wells, and small black dots show locations of vibracores. The two thin black lines connecting Cat Point to St. George Island are the old and new bridges to the island.
[Enlargement]
Conceptual illustration showing the development of the oyster reefs; view is from the south.
Figure 2: Surficial geology of the study area in Apalachicola Bay and St. George Sound.
[Enlargement]

Publications

Manuscripts

D. Twichell, L. Edmiston, B. Andrews, W. Stevenson, J. Donoghue, R. Poore, L. Osterman, 2010, Geologic controls on the recent evolution of oyster reefs in Apalachicola Bay and St. George Sound, Florida. Estuarine, Coastal and Shelf Science 88, 385-394.
Flocks, J, Twichell, D, Sanford, J, Pendleton, E, and Baldwin, W, 2009, Chapter F, Sediment sampling analysis to define quality of sand resources, in Lavoie, D., editor, Sand resources, regional geology, and coastal processes of the Chandeleur Island coastal system - an evaluation of the resilience of the Breton National Wildlife Refuge: U.S. Geological Survey Scientific Information Report 2009-5252, p. xxx-xxx.
Flocks, J., Miner, M.D., Twichell, D.C., Lavoie, D.L., and Kindinger, J., 2009, Evolution and preservation potential of fluvial and transgressive deposits on the Louisiana inner shelf: understanding depositional processes to support coastal management: Geo-Marine Letters, v. 29, p. 359-378.
Osterman, L.E., Twichell, D.C., and Poore, R.Z., 2009, Holocene evolution of Apalachicola Bay, Florida: Geo-Marine Letters, v. 29, p. 395-404.
Rogers, B., and Kulp, M., 2009, Chapter G. The St. Bernard Shoals - an outer continental shelf sedimentary deposit suitable for sandy barrier island renourishment, in Lavoie, D., ed., Sand resources, regional geology, and coastal processes of the Chandeleur Islands coastal system - an evaluation of the Breton National Wildlife Refuge: U.S. Geological Survey Scientific Information Report 2009-5252, p. xxx-xxx.
Rogers, B., and Kulp, M.A., 2009, Late Holocene chronology, origin, and evolution of the St. Bernard Shoals, northern Gulf of Mexico, USA: Geo-Marine Letters, v. 29, no. 6, p. 379-394.
Twichell, D, Pendleton, E, Baldwin, W, and Flocks, J, 2009, Geologic mapping of distribution and volume of potential sand resources, in Lavoie, D., editor, Sand resources, regional geology, and coastal processes of the Chandeleur Island coastal system - an evaluation of the resilience of the Breton National Wildlife Refuge: U.S. Geological Survey Scientific Information Report XXX, p. xxx-xxx.
Twichell, D., Pendleton, E., Baldwin, W., and Flocks, J., 2009, Chapter E. Geologic mapping of distribution and volume of potential sand resources, in Lavoie, D., editor, Sand resources, regional geology, and coastal processes of the Chandeleur Island coastal system: an evaluation of the resilience of the Breton National Wildlife Refuge: U.S. Geological Survey Scientific Information Report 2009-5252, p. xxx-xxx.
Twichell, D.C., Pendleton, E.A., Baldwin, W.E., and Flocks, J., 2009, Subsurface control on sea-floor erosional processes offshore of the Chandeleur Islands, Louisiana: Geo-Marine Letters, v. 29, no. 6, p. 349-358.
Danforth, W.W., Denny, J.F., O'Brien, T.F., Bergeron, E., Twichell, D.C., Worley, C.W., Andrews, B.D., and Irwin, B.J., 2007, USGS shallow water geophysical mapping operations using a new autonomous surface vehicle, in U.S. Hydro 2007, 15-17 May 2008, Norfolk, VA, Hydrographic Society of America.
Denny, J.F., Schwab, W.C., Twichell, D.C., O'Brien, T.F., Danforth, W.W., Foster, D.S., Bergeron, E., Worley, C.W., Irwin, B.J., Butman, B., Valentine, P.C., Baldwin, W.E., Morton, R.A., Thieler, E.R., Nichols, D.R., and Andrews, B.D., 2007, USGS advances in integrated high-resolution sea-floor mapping, in Coastal Sediments '07: Sixth International Symposium on Coastal Engineering and Science of Coastal Sediment Processes: Proceedings, New Orleans, LA, May 13-17, 2007, American Society of Civil Engineers, p. 2487-2500.
Lavoie, D., 2007, Current and future science plans for restoring a resilient coast, in Farris, G.S., Smith, G., Holm, T., Robbins, L., and Demas, C., eds., Science and the storms: the USGS response to the hurricanes of 2005: Lafayette, LA, U.S. Geological Survey, p. 265-269.

Open File Report(OFR)

Pendleton, E.A., Barras, J.A., Williams, S.J., and Twichell, D.C., 2010, Coastal vulnerability assessment of the Northern Gulf of Mexico to sea-level rise and coastal change: U.S. Geological Survey Open-File Report 2010-1146.
Twichell, D.C., Pendleton, E.A., Poore, R.Z., Osterman, L.E., and Kelso, K., 2009, Vibracore, radiocarbon, microfossil, and grain-size data from Apalachicola Bay, Florida: USGS Open-File Report 2009-1031.
Baldwin, W.E., Pendleton, E.A., and Twichell, D.C., 2008, Geophysical data from offshore of the Chandeleur Islands, Eastern Mississippi Delta, U.S. Geological Survey Open-File Report 2008-1195 (DVD-ROM)
Twichell, David C., Brian D. Andrews, Brian D., Edmiston, H. Lee, and Stevenson, William R., 2007, Geophysical Mapping of Oyster Habitats in a Shallow Estuary; Apalachicola Bay, Florida, U.S. Geological Survey Open-File Report 2006-1381

Abstracts and Presentations

Twichell, D.C. and nine others, 2009, Mapping the floor of Apalachicola Bay, Florida: Summary of acoustic mapping techniques and findings: Survey methods for shallow water habitat mapping in Northeast Department of Interior Holdings and Estuarine Research Reserves, Univ. New Hampshire.
Flocks, J., Twichell, D.C., Baldwin, W.E., Kulp, M., and Miner, M.D., 2008, Influence of antecedent geology on barrier island development, northern Chandeleur Islands, Louisiana [abstract #2462]in 2008 Ocean Sciences meeting, March 2-7, 2008, Orlando, FL, American Society of Limnology and Oceanography.
Flocks, J., Twichell, D.C., Baldwin, W.E., Pendleton, E.A., Miner, M.D., and Kulp, M., 2008, Shallow stratigraphic framework and evolution of the northern Chandeleur Islands, Louisiana [abstract]in Association of Environmental and Engineering Geologists 2008 annual meeting program with abstracts, New Orleans, LA, p. 63-64.
Miner, M.D., Kulp, M., Georgiou, I., Sallenger, A., FitzGerald, D., Flocks, J., and Twichell, D., 2008, Sediment transport trends along the Chandeleur Islands, Louisiana: Implications for island sustainability and barrier island management: AGU-ASLO Meeting
Pendleton, E.A., Twichell, D.C., and Baldwin, W.E., 2008, Documenting erosion of the St. Bernard Delta: Past and present [abstract]: Eos, Transactions - American Geophysical Union, v. 89, no. 53, Fall meeting supplement, OS43B-1292.
Twichell, D.C., Baldwin, W.E., Flocks, J.G., Pendleton, E.A., Miner, M.D., and Kulp, M., 2008, Subsurface control on sea-floor erosional processes offshore of the Chandeleur Islands, LA [abstract #1368], in 2008 Ocean Sciences meeting, March 2-7, 2008, Orlando, FL, American Society of Limnology and Oceanography.
Twichell, D.C., Edmiston, L., Andrews, B.D., Stevenson, W., Osterman, L.E., Donoghue, J., and Poore, R.Z., 2008, The development of oyster beds in Apalachicola Bay, FL during the late Holocene [abstract and poster], in Lavoie, D., and Rosen, B., eds., USGS Gulf Coast Science Conference and Florida Integrated Science Center Meeting: Proceedings with Abstracts, October 20-23, 2008, Orlando, FL: St. Petersburg, FL, U.S. Geological Survey Open-File Report 2008-1329, p. 90.
Twichell, D.C., Flocks, J.G., Miner, M.D., Baldwin, W.E., Pendleton, E.A., Kulp, M., and Georgiou, I.Y., 2008, Assessing the importance of shoreward vs. alongshore sand transport during the late Holocene evolution of the Chandeleur Islands, LA [abstract]: Geological Society of America Abstracts with Programs, v. 40, no. 6, p. 314.
Twichell, D.C., Pendleton, E.A., Baldwin, W.E., and Flocks, J., 2008, Subsurface control on sea-floor erosional processes offshore of the Chandeleur Islands, LA [abstract and poster], in Lavoie, D., and Rosen, B., eds., USGS Gulf Coast Science Conference and Florida Integrated Science Center Meeting: Proceedings with Abstracts, October 20-23, 2008, Orlando, FL: St. Petersburg, FL, U.S. Geological Survey Open-File Report 2008-1329, p. 89.
Danforth, W.W., Denny, J.F., O'Brien, T.F., Bergeron, E., Twichell, D.C., Worley, C.W., Andrews, B.D., and Irwin, B.J., 2007, USGS shallow water geophysical mapping operations using a new autonomous surface vehiclein U.S. Hydro 2007, 15-17 May 2008, Norfolk, VA, Hydrographic Society of America.
Denny, JF, Schwab, WC, Twichell, DC, O'Brien, TF, Danforth, WW, Foster, DS, Bergeron, E, Worley, CR, Irwin, BJ, Butman, B, Valentine, PC, Baldwin, WE, Morton, RA, Thieler, ER, Nichols, DR, and Andrews, BD, 2007, USGS advances in integrated high-resolution sea-floor mapping: Inner continental shelf to estuaries: Coastal Sediments 2007 Proceedings, v. 3, 14 p.
Twichell, D.C., Andrews, B.D., Bergeron, E., Edmiston, L., and Stevenson, W., 2007, Benthic mapping in Apalachicola Bay, FL: Summary of acoustic mapping techniques and findings [abstract], in Coastal GeoTools07 Proceedings, March 5-8, 2007, Myrtle Beach, SC, p. 53.
Denny, J.F., O'Brien, T.F., Bergeron, E., Twichell, D.C., Worley, C.W., Danforth, W.W., Andrews, B.D., and Irwin, B.J., 2006, Advances in shallow-water, high-resolution sea-floor mapping; integrating an autonomous surface vessel (ASV) into nearshore geophysical studies [abstract NS31B-1574]: EOS, Transactions AGU, v. 87, no. 52 Fall meeting suppl.

Other

Twichell, D.C., and Brock, J.C., 2011, Seafloor erosional processes offshore of the Chandeleur Islands, Louisiana: U.S. Geological Survey Fact Sheet 2011-3026, 2 p.
Danforth, W.W., Denny, J.F., O'Brien, T.F., Bergeron, E., Twichell, D., Worley, C.R., Andrews, B.D., and Irwin, B., 2007, USGS shallow water geophysical mapping operations using a new autonomous surface vehicle: U.S. Hydro 2007, Norfolk, VA, Conference Proceedings, CD-ROM 4
NGOM Project Homepage
Deepwater Horizon
1: Scientific Leadership 
  Information Management
2: Holocene Evolution
  Eastern Louisiana Region
  Mississippi-Alabama Region
  Climate Variability
  Mississippi River Delta Plain 
3: Recent Evolution
  Climate Variability
  Landcover Change
  Barrier Islands
  Mississippi River Delta Plain
  Landscape Change
4: 21st Century
  Landscape Structure
  Lidar/Geomorphology
  Hazard Forecast
  Hazard Vulnerability
Publications
  List by Task
  List by Subtask
  List by Type
  Meetings
  In the News
  Photos/Multimedia
  Related Websites
  Contact Information

Accessibility FOIA Privacy Policies and Notices


Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL of this page is: http://ngom.usgs.gov/task2_1/index2.php
Page Contact Information: Rodolfo J. Troche - Webmaster, 727-803-8747 x 3082
Page Last Modified: 12:24PM 05/14/2010 (RJT)